Kepler telescope discovers 100 Earth-sized planets

Nasa's Kepler telescope has discovered more than 100 Earth-sized planets orbiting alien stars.

It has also detected nine small planets within the so-called habitable zone, where conditions are favourable for liquid water - and potentially life.

The finds are contained within a catalogue of 1,284 new planets detected by Kepler - which more than doubles the previous tally.

Nasa said it was the biggest single announcement of new exoplanets.

Space agency scientists discussed the new findings in a teleconference on Tuesday.

Statistical analyses of the expanding sample of worlds helps astronomers understand how common planets like our own might be.

"If you ask yourself where is the next habitable planet likely to be, it's within about 11 light-years, which is very close," said Dr Natalie Batalha,

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Mercury's journey across Sun under way

Mercury is seen here moving across the Sun for the first time in 10 years

Skywatchers across the globe are observing Mercury transit the Sun, the little planet's third such pass of 14 it will make this century.

Mercury's sojourn between Earth and our star lasts from 11:12 until 18:42 GMT.

It will not make another transit until 2019 and then 2032.

The event is impossible - and dangerous - to view with the naked eye or binoculars, but astronomy groups worldwide are offering the chance view it through filtered telescopes.

Live views from space and ground telescopes are also available online.

They show Mercury as a tiny black circle, smaller but darker than many sunspots, slowly traversing the Sun's giant yellow disc.

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Where to view the transit of Mercury

• The UK's Royal Astronomical Society has a list of public viewing events and a guide for schools
• Nasa's Solar Dynamics Observatory is making images from its satellite available in real time
• The European Space Agency is streaming live images and hosting a Google Hangout

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Mercury spins around the Sun every 88 days, but its orbit is tilted relative to the Earth's. It is that discrepancy which makes it relatively rare for the three bodies to line up in space.

What a wonderful event for showing people Mercury - it's a hard planet to see

Prof David Rothery, Open University

From western Europe, north-western Africa and much of the Americas, Mercury's seven-and-a-half-hour glide across the Sun will be visible in its entirety. A further swathe of the planet (see map below) will catch part of the transit, depending on local sunrise and sunset times.

The only land masses to miss out completely are Australasia, far eastern Asia and Antarctica.

Because Mercury is so small - just one-third as big as Earth and, from our perspective, 1/150th of the Sun's diameter - its transit can only be glimpsed under serious magnification; the "eclipse glasses" used by thousands of people to view last year's solar eclipse will be useless.

And to avoid permanent eye damage, any telescope must be fitted with a solar filter before being trained on the Sun. The British Astronomical Association explains on its website how amateur stargazers can enjoy the spectacle safely.

This composite image traces the 2006 Mercury transit, as seen by the Soho space telescope

This photo by April Harper from Blunham, Bedfordshire, was taken after midday and sent into the BBC's Weather Watchers website

Open University's Prof David Rothery said the celestial event would not present any novel scientific opportunities - but was special nonetheless.

"From this transit, we're unlikely to learn anything we don't already know," he told BBC Inside Science. "But what a wonderful event for showing people Mercury. It's a hard planet to see.

"Historically, transits were of immense importance."

In the 1700s, for example, it was observations of Mercury and Venus slipping across the Sun that allowed astronomers, led by Edmund Halley, to pin down the dimensions of the known Solar System.

Prof Rothery is a Mercury expert and a leading scientist on the European Space Agency's BepiColombo mission to the diminutive planet, which will launch in 2017 or 2018.

Mercury has already been visited by two Nasa probes: Mariner 10 flew past in 1974 and 1975 and Messenger spent four years in orbit until its planned crash landing in 2015.

The team behind Nasa's Messenger mission has released the first topographic map of the smallest planet

Messenger spent four years in orbit taking images and measurements of Mercury

"[Messenger] told us an awful lot. It really told us we don't understand Mercury - because there's a lot of things which just don't stack up," Prof Rothery said.

"It's an airless body, with lots of craters... But there's been a long history of volcanic activity, fault activity - and the composition, that began to be revealed by Messenger, is weird.

"There's very little iron at the surface but it must have a ginormous iron core, because it generates a magnetic field - which Venus, Mars and the Moon don't."

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Gene therapy reverses sight loss and is long-lasting

By Pallab GhoshScience correspondent, BBC News

A life transformed: Joe Pepper was slowly going blind until a gene therapy reversed his sight loss.

A genetic therapy has improved the vision of patients who would otherwise have gone blind.

A clinical study has shown that the improvement is long-lasting and so the therapy is suitable to be offered as a treatment.

The researchers will apply for approval to begin trials to treat more common forms of blindness, such as macular degeneration, next year

The results have been published in the New England Journal of Medicine.

A team at Oxford University are treating a rare disorder called choroideremia. The disorder affects young men whose light-detecting cells in the backs of their eyes are dying because they have inherited a faulty gene.

Until now there has been no treatment and they gradually become blind.

The therapy involves injecting a working copy of the gene into the back of their eyes to stop more cells from dying.

The researchers found that not only does the treatment halt the disease, it revives some of the dying cells and improves the patient's vision, in some cases markedly.

A 24-year-old history teacher, Joe Pepper who works at St John's school in Leatherhead in Surrey, is the latest patient to have been treated.

Joe played for Hayes Cricket Club in Kent as a boy, but was was forced to give it up when he was 16 when his vision deteriorated.

But he could see well enough to continue his love of the game as a coach at his school.

Without the gene therapy he would have had to have given that up too within a few years, as he gradually became blind. The prospect terrified him.

"When I was 18 my vision was in a very bad place," he said, "[my sight] was degenerating at quite a speed."

He told me: "I was scared of what would have happened, I was scared of not being able to see or live the life I had.

"And now to have the belief that that's not going to happen is a weight off your shoulders."

Joe is popular with the pupils. He is jovial and laughs a lot. He teaches sport and history with a passion and enthusiasm that are infectious.

But his positive personality belies the fact that the past few years have been challenging for him as his sight worsened.

"It was really quite upsetting, not only for me, but for my family.

"I was never blind but every year there would be something new to compensate for, so my life was never steady and it was the constant changes that affected me the most, particularly when I was 18. Not being able to do what my peers were doing I found quite hard for a while."

Joe had his operation in October and began to notice an improvement soon after.

"After the operation I was looking into our garden and I could see more but I wasn't sure.

"I didn't tell my mum and dad. I didn't want to let anyone get excited until we had done a simple vision test in a week's time."

The test involved reading a sight chart of letters. Each line on the chart had progressively smaller letters.

He read line after line, going four lines beyond where he had ever read before. The medical staff were astounded.

"Everyone in the room just looked at me and I looked at them," he said reliving the moment.

"Anna, the research nurse, was taking me back out of the waiting room and she just looked at me and said it was 'fantastic' - both of us just had tears in our eyes."

Joe met his father in the waiting area. He was alarmed at the sight of his son in tears.

"He thought that it was [bad news] and he just looked at me and we both sat there in each others' arms just realising that actually it had…..." [Joe could not finish his sentence].

It was only when he was giving me his account of the joy and relief he felt with his father that the full emotional impact of the moment hit him for the first time.

After a brief pause he continued: "I cannot explain how terrifying and upsetting it was when I was younger," he continued.

"And now to know that there is so much opportunity, there is so much that I can actually do and do the things that I have actually wanted to and continue to do the things I really enjoy".

Early promise

The clinical study is small. The gene therapy has been tried out on 14 patients in the UK and 18 in the US, Canada and Germany over the past four and a half years.

The remainder have stories that are similar to Joe's.

Wayne Thompson, a 46-year-old IT worker from Staffordshire was delighted to be able to see stars in the night sky for the first time following his operation. Jonathan Wyatt a 68-year-old former lawyer says "it has opened a new chapter of my life for me when I thought that the book was about to close".

As the researchers have gained confidence in their treatment, they have tried it out on progressively younger patients who still have reasonably good vision.

Joe is the youngest and the most successful so far. This suggests that the gene therapy may be most effective on younger patients before the disease becomes irreversible.

The study also indicates that the treatment is long-lasting. The first patient received the therapy four and a half years ago and his treated eye has shown no drop-off in vision. Indeed there are still slight improvements in his vision in that eye.

This is the first indication that the treatment is viable and could be widely used on patients, according to the eye surgeon leading the trial, Prof Robert MacLaren of Oxford University:

"The concept of gene therapy is that it corrects gene defects. Ideally we should only have to do that once, because once the DNA is corrected and inserted into the correct cell, that cell should be able to continue its function as normal," he told BBC News.

"We seem to have achieved this concept of one single treatment that does not need to be repeated which is unlike traditional medicines."

Prof MacLaren says that if the next phase of larger trials goes as he anticipates, a gene therapy for choroideremia will be licensed in three years.

He has also begun to develop gene therapy trials to treat more common forms of blindness, such as retinitis pigmentosa and macular degeneration. These could begin as early as next year.

Treating these disorders will be more challenging. Choroideremia is caused by a defect in a single gene, whereas the more common forms of blindness involve several.

But Prof MacLaren believes that the choroideremia trials have laid the ground for the next phase of studies and, crucially, shown that gene therapy for blindness is safe and works.

"When I started my career as an eye surgeon when we had these patients that had inherited diseases, not only did we tell them nothing could be done but we would actually discharge them from the clinics.

"We are now calling them back in to test them, to look at them in great detail because potential treatments are available. To treat a disease at the genetic level is surely the most efficient way of treating a disease, to prevent it from happening in the first place.

"We would like to develop treatments for more common forms of blindness and this may be available in the next 5 to ten years," he told BBC News.

The Research is funded by the Health Innovation Challenge Fund which is a partnership between the Wellcome Trust and the Department of Health.

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Chameleon's tongue gives up secrets

Image copyrightSPL

Image captionThe chameleon feeds by snapping out its long tongue

Scientists have built a mathematical model to explain the secrets of the chameleon's extraordinary tongue.

It took more than 20 equations to capture mathematically how the reptile's tongue unravels at very high speed to snare insects.

The model explains the mechanics of the animal's tongue and the inherent energy build-up and rapid release.

British researchers say the insights will be useful in biomimetics - copying from nature in engineering and design.

"If you are looking at the equations they might look complex but at the heart of all of this is Newton's Second Law - the sort of thing that kids are learning in A-Levels, which is simply that you're balancing forces with accelerations," explained Derek Moulton, associate professor of mathematical biology at Oxford University.

He added: "In mathematical terms, what we've done is we've used the theory of non linear elasticity and captured the energy in these various tongue layers and then passed that potential energy to a model of kinetic energy for the tongue dynamics."

The chameleon is a reptile with many distinctive features.

Its feet have two toes facing forward and two facing backwards, like a bird; it can grasp objects with its tail; it can change colour and its tongue is among the fastest on Earth.

The chameleon's tongue is able to extend to twice the length of the body while unravelling telescopically.

Past research has shown if the tongue were a car, it could accelerate from 0 to 60 mph in one hundredth of a second.

Scientific curiosity

A team led by the University of Oxford used observations and experiments to develop a mathematical model to explain this feat.

Part of the secret of the chameleon's success, the researchers confirmed, is special stretchy tissue in their tongue.

At the core of the tongue is a bone, which is surrounded by 10-15 layers of very thin fibrous tissues, then a muscle.

"The equations are modelling the mechanics of these different layers, and the interactions of these different layers," Dr Moulton explained.

"The balance of forces and the energy contained in these different layers when the muscle - this outermost layer - contracts, which is what sets the whole thing in motion."

The research is published in the Royal Society journal, Proceedings of the Royal Society of London A.

The model could have applications in the design of soft, elastic materials for robotics.

But the scientists, who worked in collaboration with a US team, say their main drive was simply "scientific curiosity".

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